I just picked up this 27 with big shaft speedmaster 4. It has a mild 454 producing just over 500 Hp on the dyno. Trying to get it dialed in. Came with an 18" 26P 4 blade. Planed pretty good and ran well (upper 50's), just didn't have enough HP to swing it past 4300 rpms. Found a 15" 26P 4 blade on ebay. Figured it should spin it easier. Almost couldn't get on plane because it slipped so bad. Finally got it going and spun it up around 4900 rpms which is better but only 58 Mph. A bit more trim and it'll touch 5200 but it's just slipping and losing speed. My propshaft height is pretty high with the #4, about an inch above the bottom of the V. Obviously no pad or step. Trying to plan my next steps. I think I need the big diameter to give enough bite, but a little less pitch. (Its hard to find smaller pitch 26 spline props) Would a 5 blade be worth the money for more bite? Should I try a 2" spacer or an extension box? I'm planning on adding another 150-200HP into the mix in the near future so this current prop may end up being about right. But my slip still seems really high, even at neutral trim. It does throw a hell of a roost with some trim but I know that its just cool looking and not productive.

What's everyone's thoughts on this propshaft height?

Thanks Guys
-Chris

Some hulls dont like boxes plus you'd have to rework the steering.....could be the angle of the pic but looks closer to two inches up ? if you can get a spacer for a good price might try that but if it was mine Id install the new power then start tinkering because things will change........jmo